Product designers are motivated to limit power consumption in computer systems and other electronic devices. This is especially true for portable electronics, so that battery life can be extended. It is also desirable to effectively manage power consumption in desktop and enterprise-level computer systems (such as servers) to reduce heat generation and improve economic efficiencies associated with their operation.
Various sleep and hibernation modes are known for conserving power in computer systems. In such a mode, a power controller typically causes power to be removed from certain devices associated with the computer system. For example, the power controller in a portable or desktop computer may remove power from computer monitor display drivers in a sleep mode. Conventional systems may use the same type of on/off control to manage the power consumption of Dynamic Random Access Memory (DRAM) or other memory devices. For instance, in one power conservation state, the power controller may power down other devices, but leave the DRAM fully powered. In another power conservation state, the power controller may first cause DRAM content to be transferred to a hard drive; the power controller may then power down the DRAM for the remainder of the power conservation state.
Such conventional schemes have many disadvantages. For instance, where DRAM has been completely deactivated in a power conservation mode, there may be a substantial time delay upon exiting such mode to reactivate the DRAM and read data from the hard drive. Improved power conservation systems and methods are therefore needed for DRAM and other memory devices.